Camshafts are used in internal combustion engines to actuate the gas exchange valves. The cams of the camshafts usually bear against cam followers, for example bucket tappets, drag levers or valve rockers. If a camshaft is set in rotation, the cams act on the cam followers that in turn actuate the gas exchange valves. Both the opening duration and also the opening amplitude, but also the opening and closing instants of the gas exchange valves, are therefore fixed by the position and the shape of the cams.
The angular displacement of the camshaft in relation to a crankshaft in order to achieve optimized control times for various rotational speed and load states is called camshaft adjustment. One structural variant of a camshaft adjuster operates, for example, according to what is known as the swing motor principle. In so doing, a stator and a rotor are provided that lie coaxially and can be moved relative to one another. The stator and the rotor together form hydraulic chambers, referred to here simply as chambers. One chamber pair is delimited in each case by webs of the stator and is divided by a respective vane of the rotor into two chambers which act in opposite directions and the volumes of which are modified by a relative rotational movement of the rotor with respect to the stator in the opposite direction. In the maximum adjusting position, the respective vane bears against one of the edge-side webs of the stator. The relative rotational movement of the rotor takes place by an adjustment of the vane, as a hydraulic medium, such as oil, is introduced via channels into the chambers and urges the vane away. The adjustment of the rotor causes the camshaft attached to the rotor to move, for example, in the direction ‘Early’, i.e. towards an earlier opening instant of the gas exchange valves. The adjustment of the rotor in the opposite direction causes the camshaft to be moved with respect to the crankshaft in the direction ‘Late’, i.e. towards a later opening instant of the gas exchange valves. The hydraulic medium is conveyed from a central oil inlet via oil channels, which are arranged on both sides of the respective vane, into the respective chamber. The oil channels represent for example bores in the material of the rotor and this constitutes a costly embodiment.